src/com/owncloud/android/utils/BitmapUtils.java

   1 /**
   2  *   ownCloud Android client application
   3  *
   4  *   @author David A. Velasco
   5  *   Copyright (C) 2015 ownCloud Inc.
   6  *
   7  *   This program is free software: you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License version 2,
   9  *   as published by the Free Software Foundation.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20 package com.owncloud.android.utils;
  21
  22 import com.owncloud.android.lib.common.utils.Log_OC;
  23
  24 import android.graphics.Bitmap;
  25 import android.graphics.BitmapFactory;
  26 import android.graphics.Matrix;
  27 import android.graphics.BitmapFactory.Options;
  28 import android.media.ExifInterface;
  29 import android.net.Uri;
  30 import android.webkit.MimeTypeMap;
  31
  32 import java.io.File;
  33
  34 /**
  35  * Utility class with methods for decoding Bitmaps.
  36  */
  37 public class BitmapUtils {
  38
  39
  40     /**
  41      * Decodes a bitmap from a file containing it minimizing the memory use, known that the bitmap
  42      * will be drawn in a surface of reqWidth x reqHeight
  43      *
  44      * @param srcPath       Absolute path to the file containing the image.
  45      * @param reqWidth      Width of the surface where the Bitmap will be drawn on, in pixels.
  46      * @param reqHeight     Height of the surface where the Bitmap will be drawn on, in pixels.
  47      * @return
  48      */
  49     public static Bitmap decodeSampledBitmapFromFile(String srcPath, int reqWidth, int reqHeight) {
  50
  51         // set desired options that will affect the size of the bitmap
  52         final Options options = new Options();
  53         options.inScaled = true;
  54         options.inPurgeable = true;
  55         if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1) {
  56             options.inPreferQualityOverSpeed = false;
  57         }
  58         if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
  59             options.inMutable = false;
  60         }
  61
  62         // make a false load of the bitmap to get its dimensions
  63         options.inJustDecodeBounds = true;
  64
  65         BitmapFactory.decodeFile(srcPath, options);
  66
  67         // calculate factor to subsample the bitmap
  68         options.inSampleSize = calculateSampleFactor(options, reqWidth, reqHeight);
  69
  70         // decode bitmap with inSampleSize set
  71         options.inJustDecodeBounds = false;
  72         return BitmapFactory.decodeFile(srcPath, options);
  73
  74     }
  75
  76
  77     /**
  78      * Calculates a proper value for options.inSampleSize in order to decode a Bitmap minimizing
  79      * the memory overload and covering a target surface of reqWidth x reqHeight if the original
  80      * image is big enough.
  81      *
  82      * @param options       Bitmap decoding options; options.outHeight and options.inHeight should
  83      *                      be set.
  84      * @param reqWidth      Width of the surface where the Bitmap will be drawn on, in pixels.
  85      * @param reqHeight     Height of the surface where the Bitmap will be drawn on, in pixels.
  86      * @return              The largest inSampleSize value that is a power of 2 and keeps both
  87      *                      height and width larger than reqWidth and reqHeight.
  88      */
  89     private static int calculateSampleFactor(Options options, int reqWidth, int reqHeight) {
  90
  91         final int height = options.outHeight;
  92         final int width = options.outWidth;
  93         int inSampleSize = 1;
  94
  95         if (height > reqHeight || width > reqWidth) {
  96             final int halfHeight = height / 2;
  97             final int halfWidth = width / 2;
  98
  99             // calculates the largest inSampleSize value (for smallest sample) that is a power of 2 and keeps both
 100             // height and width **larger** than the requested height and width.
 101             while ((halfHeight / inSampleSize) > reqHeight
 102                     && (halfWidth / inSampleSize) > reqWidth) {
 103                 inSampleSize *= 2;
 104             }
 105         }
 106
 107         return inSampleSize;
 108     }
 109
 110     /**
 111      * Rotate bitmap according to EXIF orientation.
 112      * Cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
 113      * @param bitmap Bitmap to be rotated
 114      * @param storagePath Path to source file of bitmap. Needed for EXIF information.
 115      * @return correctly EXIF-rotated bitmap
 116      */
 117     public static Bitmap rotateImage(Bitmap bitmap, String storagePath){
 118         Bitmap resultBitmap = bitmap;
 119
 120         try
 121         {
 122             ExifInterface exifInterface = new ExifInterface(storagePath);
 123             int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
 124
 125             Matrix matrix = new Matrix();
 126
 127             // 1: nothing to do
 128
 129             // 2
 130             if (orientation == ExifInterface.ORIENTATION_FLIP_HORIZONTAL)
 131             {
 132                 matrix.postScale(-1.0f, 1.0f);
 133             }
 134             // 3
 135             else if (orientation == ExifInterface.ORIENTATION_ROTATE_180)
 136             {
 137                 matrix.postRotate(180);
 138             }
 139             // 4
 140             else if (orientation == ExifInterface.ORIENTATION_FLIP_VERTICAL)
 141             {
 142                 matrix.postScale(1.0f, -1.0f);
 143             }
 144             // 5
 145             else if (orientation == ExifInterface.ORIENTATION_TRANSPOSE)
 146             {
 147                 matrix.postRotate(-90);
 148                 matrix.postScale(1.0f, -1.0f);
 149             }
 150             // 6
 151             else if (orientation == ExifInterface.ORIENTATION_ROTATE_90)
 152             {
 153                 matrix.postRotate(90);
 154             }
 155             // 7
 156             else if (orientation == ExifInterface.ORIENTATION_TRANSVERSE)
 157             {
 158                 matrix.postRotate(90);
 159                 matrix.postScale(1.0f, -1.0f);
 160             }
 161             // 8
 162             else if (orientation == ExifInterface.ORIENTATION_ROTATE_270)
 163             {
 164                 matrix.postRotate(270);
 165             }
 166
 167             // Rotate the bitmap
 168             resultBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
 169             if (resultBitmap != bitmap) {
 170                 bitmap.recycle();
 171             }
 172         }
 173         catch (Exception exception)
 174         {
 175             Log_OC.e("BitmapUtil", "Could not rotate the image: " + storagePath);
 176         }
 177         return resultBitmap;
 178     }
 179
 180     /**
 181      * Converts an HSL color value to RGB. Conversion formula
 182      * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
 183      * Assumes h, s, and l are contained in the set [0, 1] and
 184      * returns r, g, and b in the set [0, 255].
 185      * from: http://axonflux.com/handy-rgb-to-hsl-and-rgb-to-hsv-color-model-c
 186      *
 187      * @param   integer  h       The hue
 188      * @param   Integer  s       The saturation
 189      * @param   Integer  l       The lightness
 190      * @return  Array           The RGB representation
 191      */
 192     public static int[] hslToRgb(Double h, Double s, Double l){
 193         Double r, g, b;
 194
 195         if(s == 0){
 196             r = g = b = l; // achromatic
 197         } else {
 198             Double q = l < 0.5 ? l * (1 + s) : l + s - l * s;
 199             Double p = 2 * l - q;
 200             r = hue2rgb(p, q, h + 1/3) * 255;
 201             g = hue2rgb(p, q, h) * 255;
 202             b = hue2rgb(p, q, h - 1/3) * 255;
 203         }
 204
 205
 206         int[] array = {r.intValue(), g.intValue(), b.intValue()};
 207         return array;
 208     }
 209
 210     private static Double hue2rgb(Double p, Double q, Double t){
 211         if(t < 0) t += 1;
 212         if(t > 1) t -= 1;
 213         if(t < 1/6) return p + (q - p) * 6 * t;
 214         if(t < 1/2) return q;
 215         if(t < 2/3) return p + (q - p) * (2/3 - t) * 6;
 216         return p;
 217     }
 218
 219
 220     /**
 221      * Checks if file passed is an image
 222      * @param file
 223      * @return true/false
 224      */
 225     public static boolean isImage(File file) {
 226         Uri selectedUri = Uri.fromFile(file);
 227         String fileExtension = MimeTypeMap.getFileExtensionFromUrl(selectedUri.toString().toLowerCase());
 228         String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(fileExtension);
 229
 230         return (mimeType != null && mimeType.startsWith("image/"));
 231     }
 232
 233 }